1. Field of the Invention
The present disclosure relates to turbine engine components, and more particularly to fiber optic cables such as used in imaging systems during operation of a gas turbine engine.
2. Description of Related Art
Optical fiber technology has enabled imaging systems known as industrial endoscopes (or borescopes) which are widely used in various industrial applications. Such imaging systems can provide several diagnostic advantages. For example, to inspect internal structures that are otherwise inaccessible and cannot be inspected with direct line of sight imaging or, for example, maintaining conditions of a combustor, such as a gas turbine combustor, which are diagnosed on the basis of the luminance of flames measured with a fiber optic cable during combustion.
Fiber optic cables for combustion and industrial process monitoring and diagnosis in gas turbine and aircraft engine applications require rugged equipment and a high signal level. Generally such fiber optic cables include bundles of multiple fibers. These designs can be bulky and expensive because of special components needed for coupling and packaging. Fiber optic cables also require a large minimum bend radius which is tied to the refraction index and external reflective coating on each glass fiber to prevent loss of light from the wave guide. These bend radii can be too large to thread through a traditional fuel nozzle to make any necessary sharp turns to view the combustor effectively.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved fiber optic cables for fuel nozzles. The present disclosure provides a solution for this need.